Clean up tracked artifacts and commit vitest config

Remove node_modules/ and tsconfig.tsbuildinfo from git tracking
(both already in .gitignore). Add vitest.config.js which was
missing from version control.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

vitest.config.js

@@ -0,0 +1,8 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const config_1 = require("vitest/config");
+exports.default = (0, config_1.defineConfig)({
+    test: {
+        globals: true,
+    },
+});